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 Risk abruptly changes over time  Define risk using time-to-event outcome  Is there a change in hazard?  Is this statistically significant?  What is the estimated time of change? (aka CHANGE- POINT) Change-point is defined as the time point at which an abrupt change occurs in the risk/benefit due to a treatment Definition of the Problem 15 | Change in Hazard | Rafia Bhore | 21 May 2013 | Midwest Biopharmaceutical Statistics Workshop